@cassidoo's interview question from September 18, 2022

calculateGPA.sh

#!/usr/bin/env bash
set -eu -o pipefail

# initialize vars
runningTotal="0"

# normalized grade names to point values
A="4" AMINUS="3.7"
BPLUS="3.3" B="3" BMINUS="2.7"
CPLUS="2.3" C="2" CMINUS="1.7"
DPLUS="1.3" D="1" DMINUS="0.7"
F="0"

# normalize param to grade name
normalizeGradeParam () {
	out="$( tr [':lower:'] [':upper:'] <<< "${1}" )"
	case $out in
		('A-') out="AMINUS";;
		('B+') out="BPLUS";;
		('B-') out="BMINUS";;
		('C+') out="CPLUS";;
		('C-') out="CMINUS";;
		('D+') out="DPLUS";;
		('D-') out="DMINUS";;
		(A|B|C|D|F) : ;;
		(*) out="invalid grade: ${out}";;
	esac
	echo "${out}"	
}

ARGC="$#" 
if [[ "$ARGC" -lt 1 ]]; then
	echo "Please enter at least one grade from the set"
	echo "A A- B+ B B- C+ C C- D+ D D- F"
	exit 1
fi

for ARG in "$@"; do
	grade=$( normalizeGradeParam $ARG )
	if [[ $grade == *"invalid"* ]]; then
		echo $grade
		exit 1
	fi
	runningTotal=$( echo "scale=2;$runningTotal+${!grade}" | bc )
done

echo "GPA is $runningTotal / $ARGC = $(echo "scale=2;$runningTotal/$ARGC" | bc )"

MONTASIO:scripts andrewrich$ ./calculateGPA.sh A a- B+ b B- c+ C c- D+ d D- f
GPA is 25.7 / 12 = 2.14
MONTASIO:scripts andrewrich$ ./calculateGPA.sh A a- B+ b B- c+ C c- D+ d D- f-
invalid grade: F-